| Country | Year Joined | % Correct |
|---|---|---|
| France | 1958 | 97%
|
| Germany | 1958 | 97%
|
| Spain | 1986 | 97%
|
| Belgium | 1958 | 95%
|
| Portugal | 1986 | 95%
|
| Sweden | 1995 | 95%
|
| Finland | 1995 | 94%
|
| Italy | 1958 | 94%
|
| Netherlands | 1958 | 94%
|
| United Kingdom | 1973 | 94%
|
| Austria | 1995 | 93%
|
| Poland | 2004 | 93%
|
| Slovenia | 2004 | 93%
|
| Bulgaria | 2007 | 92%
|
| Croatia | 2013 | 92%
|
| Denmark | 1973 | 92%
|
| Greece | 1981 | 92%
|
| Luxembourg | 1958 | 92%
|
| Romania | 2007 | 92%
|
| Slovakia | 2004 | 92%
|
| Estonia | 2004 | 91%
|
| Hungary | 2004 | 91%
|
| Ireland | 1973 | 91%
|
| Latvia | 2004 | 91%
|
| Lithuania | 2004 | 91%
|
| Czech Republic | 2004 | 89%
|
| Malta | 2004 | 83%
|
| Cyprus | 2004 | 81%
|